1. Field of the Invention
The present invention is broadly concerned with packaging equipment. More particularly, the present invention concerns a vacuum packaging machine of the type used for the purpose of creating evacuated and sealed packages of food.
2. Description of the Prior Art
It is known to provide a vacuum packaging apparatus for use in evacuating the air in an open-ended package and sealing the evacuated package. A typical apparatus of this type presents a chamber sized only for receipt of the open end of the package with the remainder of the package disposed outside of the chamber, and a vacuum pump communicating with the chamber for evacuating the chamber and the package through the open end. The sealing mechanism may include a heating element disposed outside the vacuum chamber and extending along the front of the base beyond the ends of the vacuum chamber. The heating element in this design is fixed to the base so that when the lid is lowered onto the base, the heating element is pressed against a portion of the package external of the chamber. Upon evacuation of the package, current is delivered to the heating element, melting the package material to seal the package closed.
U.S. Pat. No. 5,638,664 discloses an improved packaging apparatus which eliminates the problems inherent in the above types of vacuum packaging devices. The '664 patent has a package sealing element located within a concavity formed in the base, and is entirely within the confines of the evacuation chamber. However, the design also makes use of a liquid trap in the form of an elongated channel rearward of the sealing element, as well as a forward resilient member serving as a part of the vacuum seal. This base design can present problems in that the trap and seal arrangement collects liquids or other food particles and thus can be unsanitary if not cleaned on a regular basis. Furthermore, this patented design employs an elongated inflatable bladder beneath the resistance heating element which is inflated in timed relationship to air evacuation from a package. This bladder is directly coupled with the vacuum pump of the unit and thus is a closed part of the system.